By using finite element method, analysis the static response of internal force and displacement of gravity dam under water and no-load factors. The change of the stiffness ratio and the difference of dam and foundation stiffness at the dam heel and toe are considered. The stress in the key parts of the dam and the maximal displacement on the dam top are obtained. It is found that the change of foundation stiffness affects the stress of the dam, and the displacement decreases with the increasing of the foundation stiffness. Some computational results and conclusions are the theoretical basis for the optimization design of the gravity dam.